Screw extractor



Sept. 22, 1925. I 1,554,287

J. J. M GUCKIN SCREW EXTRACTOR Filed July 1924 amwm,

' m mm Patented Sept. 22, 1925.

Nurse en rENr OFFICE JoHN J. McGiIokIN, or BROOKLYN, NEW was, A'ssIcrNon T0 LorrIs scHwA B, borne BUSINESS AS STEVENS & COMPANY, on NEW YORK, N. Y.

scnnw EXTRACTOR.

Application filed July 2,

ments in Screw Extractors, of which tliefollowing is a specification. v

My invention relates to screw extractors, which are lntended to remove screw elements which cannot be grasped by the head in the ordinary way, the extractor being applied by forcing it into a hole drilled into the screw to be removed.

The objects of my invention are to so con struct the portion of the extractor which engages with the screw to'be extracted that it will be properly guided in the process of insertion, and will tend to hug to its seat during the movement of extraction, but may be readily released by a direct pull with or without a slight retrograde revolution.

In the drawings Fig. 1 is an elevation of my improved tool; Fig. 2 is an endview looking to the right on Fig. 1; and Fig. 3 is an endview looking to the left on Fig. 1.

Similar reference numerals designate similar parts in all the figures.

The shank 1 oi? the tool is provided with a suitable portion as 2,. wherebyitmay be gripped by a turning tool; and it is provided at its other end with a preferably reduced portion '3 of substantially the same diameter as the hole into which the extractor is to be inserted, so that the cylindrical part 3 may make a snug lit in said hole. A socket or annular groove etis formed around this reduced portion 3, leaving a terminal 5 with substantially the same diameter as the'portion 0.

On the body of the. portion 3 are formed ribs 6, prefe 'a-bly having comparatively acute-angled outer edges, andbeing carried from therecess 4 back along the reduced portion 3 for a considerable distance with very slight lateral deflection. ings I have illustrated the tool as being provided with four suchribs, but it will be readily understood that the number may be varied as is desirable to accommodate the tool to the particular work in view.

The tool is used by first drilling a hole, of substantially thesame diameter as the ter- In the draw 1924. Serial-No. 723,798.

niinal 5 and the portion 3, into the body of the screw element to be extracted, inserting the terminal 5 in the hole, and then driving the tool down thereinto, the ribs 6 directly overlap the edges of the hole so that they gouge out seats in the metal of the screw element to receive themselves as the tool is driven home, the cuttings or scraps of metal gouged out by the ribs being forced before them and finding accommodation in the scrap receiving recess 4 without clogging the tool.

As the tool forces itself home, the increa ing twist of the ribs will cause them to tol low their channels in the screw element; so that a very firm connection will be established between the tool and the screw to be extracted. The ribs 6 having a left-hand pitch, tend to hug the tool down into'its socket during the left-hand movement of unseating an ordinary right-hand screw. And yet the wedging of the extractor into the socket in the screw, will not be such that any considerable degree of, if any, right-hand rotation will be necessary to .unseat it'from the screw. In fact, a sharp blow upon the screw element, with a haminer or the like, will usually suiiice to drive it oif of the extractor, the deflection ofthe flanges being so slight that the tool will not jam against such a movement of. separation.

By means of my improvement I secure a tool which can he simply and eiiectually connected with a screw element to be extracted, by drivingit into a cylindrical socket, which will positively and etlectively grip the element to be extracted, and may be readily separated therefrom by direct longitudinal movement.

It will be understood that I have illustrated and described a typical form of the embodiment of my improvement and that the details of construction may be varied, v a

surfaced longitudinal cylindrical sockets therein, provided with a cylindrical terminal portion of substantially the same diameter as the socket into which it is to be forced, said portion having an annular scrap-receiving recess therein and longitudinal cutting ribs thereupon above said recess, the ends of which are adapted directly to overlap the deflection only, compared with the deflection of the screws thread, from the longitudinal axis of the tool.

JOHN J. MCGUCKIN. 

